Two container vessels, one of them Singapore-registered, collided off Pasir Gudang on Tuesday.

The Maritime and Port Authority of Singapore (MPA) said it was notified by the Johor Port Authority (JPA) of a collision between a Singapore-registered container vessel WAN HAI 301 and a Gibraltar-registered container vessel APL DENVER off Pasir Gudang Port at 11.50pm on Tuesday.

One of the bunker tanks on the APL DENVER was reportedly damaged and spilled approximately 300 tonnes of oil, MPA said in a press release on Wednesday.

JPA has deployed four anti-pollution craft and an oil boom to contain the oil spill.

Some oil patches were spotted in Singapore, with the spillage contained off the western of Pulau Ubin.

MPA said it has activated eight anti-pollution craft with dispersant spraying capabilities to clean up the oil.

There have been no reports of injury and traffic in the East Johor Straits and Singapore's port operations remain unaffected, MPA said.

This morning two tankers collided 30km off the Belgian coast. This has meantime been confirmed by the Maritime Rescue and Coordination Centre (MRCC). Only material damage was reported.

How the accident could happen is still under investigation. The tanker "Ridgebury Kathrine Z" (Marshall Islands flag) was empty and at anchor at Westhinder anchorage when it was struck by the "Maistros" (Liberian flag) which was loaded. It is currently being examined what cargo the "Maistros" was carrying.

Authorities are checking the extent of the damage and what the desintation of both vessels is. Based on their findings it will be decided if the vessels can continue their voyage.